Sluice feeders for introducing finely divided chips into vessels under pressure

ABSTRACT

A sluice feeder for introducing finely divided vegetable material (hereinafte referred to as &#34;chips&#34;) into a pressure vessel, in which the sluice feeder is formed with a rotor encased within a housing having chip inlet and outlet openings, and liquid inlet and outlet openings. The rotor is formed with a plurality of chip receiving pockets extending axially over the rotor. Extending along one of the journals of the rotor in alignment with each pocket is a liquid conducting channel leading from the rotor pocket to the end of the journal. By forming the liquid feed channels to extend along the longitudinal axis of the journals, to the rotor, the number of rotor pockets for receipt of the chips may be significantly increased.

x- 1972 R. a. REINHALL 3,681,192

, SLUICE FEEDERS FOR INTRODUCING FINELY DIVIDED QHIPS INTO VESSELS UNDER PRESSURE Filed June 13, 1969 llllllllllllllllll A \\\dn E 'INVENTOR B ROLF'BERTIL REINHALL Y A ITORNEY US. Cl. 162-246 5 Claims ABSTRACT OF THE DISCLOSURE A sluice feeder for introducing finely divided vegetable material (hereinafter referred to as chips) into a pressure vessel, in which the sluice feeder is formed with a rotor encased within a housing having chip inlet and outlet openings, and liquid inlet and outlet openings. The rotor is formed with a plurality of chip receiving pockets extending axially over the rotor. Extending along one of the journals of the rotor in alignment with each pocket is a liquid conducting channel leading from the rotor pocket to the end of the journal. By forming the liquid feed channels to extend along the longitudinal axis of the journals, to the rotor, the number of rotor pockets for receipt of the chips may be significantly increased.

BACKGROUND OF INVENTION This invention relates to sluice feeders for introducing finely divided material, into vessels under pressure.

In various processes of continuously treating finely divided vegetable material (hereinafter referred to a chips), it is often essential that the chips are fed into vessels under pressure without subjecting the chips to too strong mechanical action. In many cases the feeding must be effected directly into the fluid in the pressure vessel without previously passing the chips through an atmosphere in which the chips might be exposed to undesirable action. This is often the case in continuous cellulose digestion processes for production of various kinds of sulfite or sulfate pulp. In general the chips must be well impregnated with digesting liquor before they are heated and exposed to the digesting temperature.

To achieve as good an effect as possible, the impregnation can be performed with digestion liquors subject to pressure, and in such a manner that the chips after having been de-aerated, either by moistening with steam or evacuation, are directly fed into the digestion liquor without prior exposure to air or other non-condensable gases, or exposure to the action of vapor.

At the start of the impregnation cycle the temperature may be low, which is of importance primarily when the impregnation is to be made with sulfite solutions in which case the temperature must not considerably exceed 120- 130 C. if formation of dark cores in the chips is to be avoided. This implies that the digestion liquor generally is under a hydrostatic pressure in that zone into which the chips are fed and that this liquid pressure is higher than the vapor pressure of the liquid within said zones. The liquid pressure in the impregnation step may vary within wide limits depending on the quality of the chips and the digestion method such as between 3 and 20 atmospheres and more, for example.

In continuous impregnation processes it is suitable to construct the impregnation vessel as a vertical cylinder into which the chips are fed to form a column extending from the bottom and up through the digestion liquor. It is easy under such conditions to maintain a very great United States Patent 0 "ice temperature gradient in the liquid which means that in the bottom layer, where the chips are introduced, the temperature can be kept low, below C., in relation to the top layer where it may have a digestion temperature, which is from to 200 C. Depending on the higher specific weight of the cold liquid and the obstruction of the convection flow by the chips column the difference in temperature can practically be maintained at a constant value. The introduction of chips thus can to advantage be efiected at the bottom of the impregnation vessel.

A feeding of the chips column from below in upward direction is of interest when the digestion is elfected in vapor phase because it is possible in a simple manner to transfer the impregnated chips from the top portion of the impregnation vessel to the digester without free digestion liquid becoming entrained. Then it is a condition that approximately the same vapor-gas pressure prevails in both the impregnation vessel and in the digester.

However, if the impregnation is conducted at another pressure than that prevailing in the digester, it can be more suitable to feed the chips from the top in a downward direction and to withdraw them at the bottom of the impregnation vessel. Then the chips must be sluiced out with an adequate quantity of free digestion liquid which, if the subsequent decomposition is conducted in vapor phase, must be separated off at the sluicing-out step and, if desired, be recycled to the impregnation vessel. Sometimes difficulties can arise in transferring the material from a vessel under pressure to another due to the consistency of the material, in particular as far as the discharge from the feeding device is in consideration.

BRIEF DESCRIPTION OF INVENTION The invention relates to a sluice feeder for introducing chips into a pressure vessel, which sluice feeder comprises a sluicing rotor formed with at least one pocket and which is carried by journals in a housing which is provided with tubular feed and discharge sockets for the material. Such a sluice feeder is in itself a simple and reliable device which makes it possible to continuously transfer solid material into the pressure vessel, the sluicing rotor in all positions sealing against the vapor or liquid pressure and simultaneously feeding the solid material without exposing it to any danger of becoming damaged by mechanical action. If the material is fed into a vapor or gas space the pockets are usually emptied easily but, as mentioned above, in some case difliculties may arise due to the properties of the material. However, when it is a question of feeding chips directly into a liquid or a mixture of chips and liquid, very difficult problems may arise in connection with the emptying of the pockets, and the difiiculties become still more serious when the introduction into the mixture of chips and liquid must be effected at the bottom of the pressure vessel or where a chips pressure prevails which furthermore renders difiicult the emptying of the sluice feeder.

One main object of the invention is to provide a sluice feeder which to a high degree complies with the requests in the respects intimated hereinbefore and thus permits a rapid and complete emptying of the pockets simultaneously as the volume of said pockets can be utilized maximally for the feed proper of the chips. According to one main feature of the invention each pocket is connected to a channel formed to extend through a journal and disposed during rotation of the rotor to be brought to communicate with a drain for liquid when the pocket is positioned in front of the feed socket, and an inlet for liquid when the pocket is positioned in front of the disEharge socket.

3 BRIEF DESCRIPTION OF DRAWINGS Further objects and advantages of the invention will become apparent from the following description considered in connection with the accommpanying drawings, which form part of this specification and of which:

FIG. 1 is a vertical longitudinal sectional view of a sluice feeder constructed according to the invention and an element connected thereto.

FIG. 2 is a sectional view following the line II--II of FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENT Referring now to the drawings the sluice feeder illustrated in FIGS. 1 and 2 consists mainly of a cylindrical rotor 1, having a shaft, which has one or several pockets 2 and is mounted within a housing 3. The lateral Walls 4 of the rotor are machined in a lathe to present a cylindrical circumference so that the rotor can rotate in a stuffing box 5 which at the same time in a pressure-proof manner seals the pockets from the ambient atmosphere. Then the mounting in bearings of the rotor in the housing can be made without necessitating its journals 30, 32 to be sealed against the interior superatmospheric pressure and no risk exists that vapor or liquid can penetrate into the bearings 6 and 7, which retain the journals in their predetermined positions. The feed opening 8 and the discharge opening 9 in the housing are formed for pressure-proof connection to conduits, containers or pressure vessels. Each pocket 2 is in connection with its iridividual channel 10 extending in the longitudinal direction of the journal 32 and opening at the end of said journal. All channels are located in one of the journals, in the present case the journal 32. Each pocket may in addition be provided with a sieve 11, which prevents chips from entering into the channel and which ensures that the bottom section of the entire pocket is in connection or communicates with the channel. Each channel has a lateral aperture 12 which opens at the outer circumference of the journal. All lateral apertures 12 are located in the same plane at right angles to the center line of the axis of rotation of the rotor. The apertures 12 are sealed against the ambient atmosphere by a sleeve 13 rigidly anchored on, and enclosing the journal 32 and formed for cooperation with a stufiing box 14 in which the journal 32 is rotatably mounted.

At its bottom side the sleeve 13 has an opening 16 which is located in front of a connection piece 15 in a casing 34 mounted around the sleeve and the stuffing box 14. The connection piece 15 is in turn in connection with a conduit 36 for feed of liquid to that pocket 2, which during rotation of the rotor just is in open communication with the discharge opening 9. In this position the channel 10 of this pocket with its aperture 12 communicates with the opening 16 and the connection piece 15. The channels 10 have open ends in the plane of end face of the journal 32 where they or a perforated plate 38 cooperate with a casing 17 rigidly secured within the housing 3 and with its plane bottom bearing against the plate 39 and sealing against the journal by means of a stufiing box 19. The plane bottom of the casing 17 has an opening 20 through which liquid can be withdrawn from that pocket 2, the channel 10 of which due to rotation of the rotor is positioned in front of said opening. The other channels 10 are thus sealed from the ambient atmosphere. The opening 20 is positioned so thatopen communication is only established when a pocket 2 is turned upwardly and therefore is positioned exactly in front of the feed socket 8. Through the casing 17 and a pipe 21 connected thereto liquid is withdrawn, if desired by means of a pump.

The housing 3 for the rotor 1 is equipped with fluid passages 22, 23 (FIG. 2) through which vapor and liquid, respectively, can be withdrawn from, or supplied to, the pockets after they have passed the feed opening 8 and the 4 outlet opening 9, respectively. The other journal 30 of the sluicing rotor is connected to a driving means 24.

In the embodiment shown the sluice feeder is combined with a cylindrical or conical screw conveyer 25, which is surrounded by a trough 26 of a corresponding shape. Preferably, the screw conveyer 25 is mounted horizontally and its trough is in open communication with the discharge socket 9 through a vertical connection piece 40. The trough 26 has a prolongation in the shape of a horizontal cylindrical sieve 27, which is connected to a pressure vessel 42. The sieve or perforated prolongation 27 is enclosed by a casing 28 from which a conduit 44 extends to the suction side of a pump 29 the pressure side of which is in connection with a pipe 36.

Mounted on the feed opening 8 is a vessel 46 within which the chips are treated with steam or liquid, for example, at atmospheric pressure or under a higher pressure. The chips are conducted from the vessel 46 into the pockets 2 as these during rotation of the rotor 1 come to communication with the feed opening 8. The chips are accompanied by condensate or liquid and due to the fact that the channel 10 of the pocket 2 is in connection with the discharge pipe 21 through the opening 20 in the casing 17, liquid will be sucked off from the pocket. After rotation over approximately a half of one revolution the same pocket will be in communication with the discharge opening 9 and at the same time its channel 10 with the open connection pieces 16 and 15 so that liquid is pumped into the channel 10 and thus rapidly and effectively empties the pocket of its chips content. Now the chips are conducted to the conveyer 25 and by the action of the same in the direction towards the pressure vessel 42. Under this movement the chips pass through the sieve 27 by which liquid is removed to be supplied through the pump 29 to the next following pocket 2 when this has taken discharge position. The liquid which in this way is supplied to the sluice feeder may also, at least partially, be withdrawn from the pressure vessel 42. The passage of the chips from the sluice feeder to the pressure vessel is effected by means of an entirely closed conveyer which is filled with liquid that is under the same pressure as that prevailing in the pressure vessel. The chips in the pockets 2 in turn to be emptied are Washed down into the conveyer, which together with the liquid flow created thereby mechanically feeds the chips into the vessel 42 without passing through any gas or vapor space. Liquid may be present in the vessel 42 above the level at which the chips are introduced into the vessel.

The sluice feeder may in certain cases be used for particle material of other kind than vegetable material provided that the same conditions exist.

While one more or less specific embodiment of the invention has been shown and described, it is to be understood that this is for purpose of illustration only, and that the invention is not to be limited thereby, but its scope is to be determined by the appended claims.

What is claimed is:

1. A sluice feeder for introducing chips into a pressure vessel, said feeder comprising:

a housing formed with feed and discharge openings for the chips; a sluicing rotor in said housing having a shaft; a plurality of pocket members formed circumferentially on said shaft; journals on opposite ends of said rotor to support the same for rotation in said housing; axially extending channel means formed circumferentially around and next to said shaft in one of said journals, said channel means extending from said pocket members on said rotor towards and beyond the said one journal; a drain passage in said housing beyond said journal and to which said channel means extend, said drain passage being positioned to receive fluid from said channel means when a pocket member from which said'channel means extends is oriented in the portion of the circumferential path of the rotor to register with a feed opening to receive chips from said pocket member through said feed opening in said housing; and a fluid inlet passage in said housing positioned to direct fluid into a channel means when the pocket member to which said channel means extends is oriented in the portion of the circumferential path of the rotor to register with a discharge opening, to discharge chips through said discharged opening in said housing.

2. A sluice feeder as defined in claim 1, wherein said channel means have open ends disposed axially in the plane end surface of said journal; a casing in said hous ing at the end of said journal having said channel means; a wall on said casing having an opening adapted upon rotation of the rotor, to establish open communication in sequence between said casing and each one of said channel means.

3. In a sluice feeder as defined in claim 1, a conveyor means connected to said discharge opening and adapted to withdraw liquid flowing chips prior to the introduction of said chips into said pressure vessel, and a pump member adapted to recycle said liquid at least partly through a channel to the sluice feeder for flushing out the chip content of the succeeding pocket member on the rotor.

4. In a sluice feeder as defined in claim 3, wherein said conveyor means consists of a screw member disposed within a trough-shaped sleeve member, said sleeve member being formed partly as a sieve and being provided with a casing said casing being connected with a pump member for recycling liquid from said casing to the pockets of the sluice rotor.

5. In a sluice feeder as defined in claim 1, wherein the housing enclosing the sluice rotor is equipped with connection pieces, for, respectively, draining liquid from, and supplying liquid to, said pocket members through said channel means after their passage in the portion of their said path beyond the feed opening and after their passage in the portion of their said path beyond the discharge opening.

References Cited UNITED STATES PATENTS 2,459,180 1/ 1949 Richter 162246 X 3 ,180,789 4/ 1965 Fuchiwaki 162-52 X 3,446,404 5/ 1969 Mehta 222-368 X FOREIGN PATENTS 862,400 1/ 1953 Germany 162-246 S. LEON BASHORE, Primary Examiner A. DANDREA, JR., Assistant Examiner US. Cl. X.R. 162-52: 222-368 

